The invention relates to a wind turbine, more specifically to a rotor assembly for a wind turbine.
Wind turbines are often used to generate electrical energy by converting the kinetic energy of the wind to electrical energy. A wind turbine comprising a horizontal shaft comprises a tower, a nacelle and a rotor assembly with a plurality of blades. The rotor assembly is mounted in the nacelle by means of a shaft which is directly or indirectly connected to a generator for generating electrical energy.
A known wind turbine is described in WO2008/067083, which discloses a wind turbine with a rotor assembly. Said rotor assembly comprises a central hub with a central rotation axis and a plurality of blades, each of which is attached to the central hub by its first central end and the longitudinal axis of which extends substantially radially with respect to the central rotation axis up to its second radial end. These blades each comprise a spreader which is arranged at the location of an intermediate point situated between the first central end and the second radial end. This spreader cooperates with a cable system which anchors the blade to the central hub via three cables in order thus to reinforce the blade structure. However, in order to anchor the cables to the central hub, an auxiliary wheel is required, whose important function is to provide a wider base for the attachment points for the cables in order to reduce the forces which are generated in the cables. In particular, the forces which are generated in the cables as a result of the deformation of the blade transversely to the central rotation axis.
Another wind turbine comprising a rotor with blades having a spreader and a cable system is known from WO2008/111841. In order to widen the base for the cables which have to absorb deformation transversely to the rotation axis, these cables are attached to the nearby blades. However, in this way, this deformation is absorbed less efficiently, since the supporting effect of these cables is nullified upon similar deformation of all the blades. Furthermore, the cable system is supplemented by a structure with rods which extend from the spreader to the central hub and which also have to absorb pressure forces, thus limiting their length. This limits the distance from the spreader to the central rotation axis.
Yet another such wind turbine is known from DE19606359; this mechanism is only able to absorb deformation of the blade along the central rotation axis. In addition, this also uses a rod mechanism, thus limiting their length and therefore limiting the distance from the spreader to the rotation axis.
As a result thereof, there is a need for a rotor assembly for a wind turbine which overcomes the abovementioned drawbacks and more particularly a rotor assembly for a wind turbine comprising blades with an improved cable system so that the blades can offer more resistance to the load to which they are subjected and can be made in a simpler manner and more lightweight.